package de.dopichaj.labrador.search.prune;

import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

import org.apache.log4j.Logger;

import de.dopichaj.labrador.search.hit.Hit;
import de.dopichaj.labrador.search.hit.HitHierarchyTree;


/**
 * This class implements a pruner for the INEX 2006 Best in Context task.
 * Works by selecting one of the hits with the highest scores.
 */
public final class BestInContextPruner implements ResultTreePruner {

    private static final Logger log =
        Logger.getLogger(BestInContextPruner.class);
    
    public void prune(HitHierarchyTree tree) {
        
        final Collection<Hit> allHits = tree.getAllHits();
        if (allHits.size() == 0) {
            log.warn("Trying to prune document with no hits");
            return;
        }

        // find the hits with the highest score
        float highScore = 0;
        Set<Hit> highScoreHits = new HashSet<Hit>();
        for (Hit hit : allHits) {
            if (hit.getScore() > highScore) {
                highScore = hit.getScore();
                highScoreHits = new HashSet<Hit>();
                highScoreHits.add(hit);
            } else if (hit.getScore() == highScore) {
                highScoreHits.add(hit);
            }
        }
        
        // choose one hit from these hits
        final Hit bestHit = highScoreHits.iterator().next();
        
        // exclude all but the best hit from the results
        for (Hit hit : tree.getAllHits()) {
            if (hit != bestHit) {
                tree.removeFromResults(hit);
            }
        }
    }

    public String getDescription() {
        return "Best in context";
    }
}
/*
Copyright (c) 2005-2007 Philipp Dopichaj

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/